Production of colored photographic images



Patented Jan. 13, 1942 PRODUCTION O FCOLORED PHOTOGRAPHIC WAGES JohnHubert Reindorp, Ilford, England, assignor to Ilford Limited, Ilford,Essex, England, a

British company No Drawing. Application July 24, 1939, Serial No.286,281. In Great Britain August 3, 1938 13 Claims.

This invention relates to the production of colored photographic imagesby color development.

It is known that a colored image may be formed simultaneously with thesilver image obtained by developing a silver halide emulsion with anaromatic amino developing agent if a substance known as a color formeris present, for example, in the developing solution or in the silverhalideemulsion. The colored image may be revealed by bleaching out thesilver image with Farmer's Reducer or other photographic bleachingagent.

It is an object of this invention to provide a new range of colorformers. A further object of the invention is to provide a methodofproducing color photographic images with the aid of such color formersand a still further object is to provide light sensitive silver halidephotographic materials containing 1 the new color formers. 1

Other objects of the invention will appear hereinafter.

According (to the present invention in a process of color development inwhich a silver halide photographic emulsion is developed with anaromatic amino compound as a developer in the presence of acolor-former, the color-former employed is a malonic acid mono-estermono-amide i. e. an organic compound of the general formula:

where R1 and R2 represent hydrogen atoms or alkyl, aryl, aralkyl orheterocyclic groups (although they do not necessarily represent the sameatoms or groups) or they represent groups linked together as a singlecyclic grouping, and R3 represents an alkyl, aryl or aralkyl group.Thus, for example, R1 may be a hydrogen atom, a methyl, ethyl, propyl orother alkyl group, a phenyl or other aryl group, a benzyl or otheraralkyl group, a thiazole, thiazoline, oxazole, oxazoline, slenazole,selenazoline, pyridine, quincline, indolenine, diazine (e. g.pyrimidine, and quinazoline) thiodiazole group, or a substituted orunsubstituded polycyclic group such as the benzthiazole, naphthathiazoleand anthrathiazole groups, R2 may also be a hydrogen atom or any of theabove mentioned groups although in any one compound it is notnecessarily the same as 131'. Further, R1 and R1. may together form asingle cyclic grouping, for example, a

' dolegroup. R3 may be, for example, a methyl ethyl, propyl or butylgroup, a phenyl group or a benzyl group.

The groups R1, R2 and R3 may themselves be substituted, e. g. by halogenatoms, by alkyl, aryl, aralkyl and other hydrocarbon groups, or by nitrogroups, hydroxy groups, amino groups,'substi-- tuted amino groups,alkoxy groups or carbethoxy alkyl groups. Those compounds which containsubstituted alkoxy groups yield, in general, colors of especialbrilliance.

The preferred compounds for use according to the present invention arecompounds of the type described above where R1 is a hydrogen atom and R2is a substituted or unsubstituted phenyl group, suitable substituents inthe phenyl group being halogen atoms or nitro, hydroxy, alkoxy or aminogroups. Typical compounds of this type are malonis acid mono ethyl estermono-oanisidide and malonic acid mono ethyl .ester mono-o-chloranilide.

The compounds to be used as color formers in accordance with theinvention. may be prepared by any suitable method. A convenient methodis to condense a compound of the type XCOCH2--COOR3 where R3 has themeaning assigned to it above and X is a halogen atom or an alkoxy groupwith a compound of the type Nil R. where R1 and R2 have the meaningsassigned to them above. Thus, for example, malonic acid mono ethyl estermono-'o-anisididemay be prepared by condensing malonic acidmonoethylester mono acid chloride or malonic acid diethyl ester witho-anisidine. Malonic acid mono ethyl ester mono-o-chloranilide may beprepared by a similar condensation using o-chloraniline instead ofo-anisidine.

The color-formers of the invention may be "incorporated in thedeveloping solution or in the photographic silver halide emulsion. Ingeneral, they are very insoluble in water and have little tendency todiffuse from one layer to another when incorporated in the emulsionlayers of a multi-layer film or to diffuse into processing baths.Moreover, the compounds show a good resistance to the bleaching actionof the sulphites frequently included in developing compositions.

Suitable aromatic amino compounds which may be employed as thedevelopers in conjunction with the color-formers of this invention arederivatives of p-phenylene diamines and particularly of the asymmetricdialkyl-p-phenylene diamines, e. g. p-aminodimethylaniline,p-aminodiethylaniline and p-aminodibutylaniline. Other developing agentswhich may be used include pphenylene-diamine itself,p-methylaminoaniline, p-ethylaminoaniline and p-aminophenol,N.N-diethyl-o-phenylene-diamine, chloro-p-phenylene diamine,1.2.5-toluylenediamine, -2-amino-5-.diethyl-aminotoluene,N-p-aminophenylpiperidine, N methyl-N-hydroxyethyl-p-phenylenediamine,N-butyl-N-hydroxyethyl-p-phenylenediamine, 2- amino 5(N-p-hydroxyethyl-Nbutyl) aminotoluene and its dihydrochloride andu-vdihydroxypropyl-p-phenylene diamine. These aromatic amino-developingagents may be used in the form of their salts, which may be either inorganic or organic. The salts are in general more stable than the freebases. As examples of suitable salts mention is made of thehydrochlorides, sulfates and acetates.

In the succeeding examples, the following solution is given by way ofexample as illustrating the nature of developing solutions which may beemployed embodying a color former in accordance with the invention.

Developing solution A Diethyl-p-phenylenediaminehydrochloride grams 1Sodium carbonate (crystals) NazCOslOI-IzO 80 Sodium sulphite (crystals)Na2SO37H2O dO 12.5 Color former solution (1% or saturated solution,whichever is weaker) ccs 100 Water to make 1itre 1 The color former isdissolved in a suitable water-miscible solvent such as ethyl alcohol orethylene glycol mono-methyl ether. The sodium sulphite may be omitted ifdesired.

A suitable development time, using this solution, is two minutes, at atemperature of 65 F.

Th following specific examples illustrate the method of production ofthe new color formers, and their use:

EXAMPLE 1 Malom'c acid mono ethyl ester mono-o-anisidide cooled solutionwas filtered.

The filtrate was then diluted to four times its volume with petroleumether and cooled in a freezing mixture, whereupon the malonic acid monoethyl ester mono-o-anisidide separated out. M. P. 63-65 C.

Developing solution A, when including this compound and used for thedevelopment of photographic silver halide images, produces a brilliantyellow image together with the silver image.

EXAMPLE 2 Melanie acid mono ethyl ester mono-flnaphthalidc EXAMPLE 3Melanie acid mono ethyl ester mono-m- Y nitram'lide 10 cos. ofdiethylmalonate and 4.08 gms. of mnitraniline were heated together in anoil bath for three hours at 130-140 C.

The excess diethylmalonate was then distilled off in vacuo and theresidue was warmed with 60 ccs. of dry ethyl alcohol. The mixture wasthen cooled in a freezing mixture and filtered. The filtrate wasevaporated on a water bath to remove the ethyl alcohol and Water wasadded. The mixture was then cooled in ice and filtered. The residue wasthen boiled up with benzene and filtered hot; the filtrate wasevaporated to 10 ccs. and allowed to cool, whereupon yellow crys tals ofmalonic acid mono ethyl ester mono-mnitranilide separated. M. P. 48 C.

Developing solution A when including this compound and used for thedevelopment of photographic silver h-alide images produces a brightyellow image together with the silver ima e.

EXAMPLE 4 Malonz'c acid mono ethyl ester monoo-hydroxyanilide Q- NH- 00-cm 00- 002m 5.45 gms. of o-amino-phenol and 40 gms. of diethylmalonatewere heated in an oil bath, for three hours, at C. On cooling, a brownsolid, M. P. 106 C. separated and this was recrystallised from benzene.Developing solution A, when including this compound and used for thedevelopment of photographic silver halide images produces a deep greenimage together with the silver image.

EXAMPLE 5 1-w-carbethoryacetylamino benzthiazole o- Nllc 0 cmo o (,n,

4.5 gms. of l-amino-benzthiazole were dissolved by warming in 200 ccs.of xylene and the solution was slowly added to a solution of 9.6 gms. ofdiethylmalonate in 15 ccs. of xylene and contain ing two drops ofpyridine, the addition of the 1- amino-benzthiazole being effected overa period of about thirty minutes.

During this process the solutions were maintained at boiling and about100 cos. of the xylene was removed. On cooling the products, a yellowsolid separated, which on recrystallisation from ethyl alcohol had amelting point of 180 C. Developing solution A when including thiscompound and used for the development of photographic silver halideimages produces an orangebrown image together with the silverimage.

EXAMPLE 6 This example illustrates the incorporation of thecolor-formers of this invention in emulsion layers. 20 cos. of 1%solution in ethylene glycol mono-methyl ether of malonic acid mono ethylester mono-o-anisidide were added to 25 cos. of aqueous solution ofgelatin and the mixture added to 50 cos. of a meltedphotographiMGa'slight emulsion containing approximately gms. of silverhalide, principally silver chloride, per

pound weight of emulsion. The emulsion thus prepared-was coated on'apaper support and dried. The emulsion coated paper was exposed under anegative and was then developed with a developing solution of theconstitution of Developing solution A excluding the color former butincluding an equivalent quantity'of the water miscible liquid such asethyl alcohol or ethylene glycol mono methyl ether. A brilliant yellowimage was produced together with the silver image.

In each of the above examples the dye image may be revealed by bleachingout the silver image with Farmer's Reducer or other known photo'-graphic bleaching agent.

In addition to the specific color formers described above, the followingare examples of color formers which may be prepared and used accordingto this invention:

Malonic acid mono ethyl ester mono-p-anisidide Malonic acid mono ethylester mono-p-nitroanilide Malonic acid mono ethyl estermono-anaphthalide l-w-carbethoxy acetylamino-S ethoxy benzthiazoleMalonic acid mono ethyl ester mono anilide Malonic acid mono ethyl estermono-o-nitroanilide Malonic acid mono ethyl ester bethoxy-anilideN.N'-di-carbethoxyacetyl benzidine 1-w-carbethoxyacetylamino-2-hydroxy4:5 dimethylbenzene Malonic acid di-o-hydroxy-p-nitroanilide Malonicacid mono ethyl ester mono-o-chloranilide The process of developmentemploying the color formers in accordance with the present invention maybe applied either to a latent image in an emulsion of a silver halidewhich has been exposed to the action of light, for example, in

mono-p-cara camera or behind a photographic negative image; or it may beapplied to the residual silver halide left when an initial reducedsilver image has been dissolved away as in the reversal process ofdevelopment; or it may be applied to a developed photographic image inmetallic silver which has been fixed by the removal of unchanged silverhalide, and subsequently converted to a developable silver salt by meansof known photographic bleaching agents. In the last two cases theresidual silver halide and the silver salt respectively may be madedevelopable by the action of light or in any other way, e. g. bytreatment with sodium arsenite.

The production of colored images by means of the color formers of thisinvention may be applied to colloid layers sensitised by bichromate.Thus the color formers may be incorporated in colloid layers (e. g.gelatin, gum arabic or albumin), the layers exposed, the unexposedcolloid removed, e. g. by treatment with hot water, and the colordeveloped in the exposed portions by treatment withp-nitro'so-dialkyl-aniline or its derivatives.

I claim:

1. A photographic color forming developer which comprises an aromaticamino developing compound and a color former which is a malonic acidmono-ester mono-amide having a methylene radical attached directly tothe two carbonyl radicals of the malonic acid nucleus.

2. A photographic color forming developer which comprises an aromaticamino developing compound and a color former of the general formula:

wherein R1 and R2 are groups selected from the class consisting ofhydrogen atoms and substituted and unsubstituted hydrocarbon groups andheterocyclic groups, and R3 is a group selected from the classconsisting of substituted and unsubstituted hydrocarbon groups.

3. A photographic color forming developer which comprises an asymmetricdi-alkyl-p-phenylene diamine and a color former which is a malonic acidmono-ester mono-amide having a methylene radical attached directly tothe two carbonyl radicals of the malonic acid nucleus.

4. A method of producing a colored image in a silver halide emulsionwhich comprises developing the emulsion with an aromatic aminodeveloping agent in the presence of a color former which is a malonicacid mono-ester mono-amide having a methylene radical attached directlyto the two carbonyl radicals of the malonic acid nucleus.

5. A method of producing a colored image in a silver halide emulsionwhich comprises developing the emulsion withan aromatic amino developingagent in the presence of a color former of the general formula:

ncoomcoom wherein R1 and R2 are groups selected from the classconsisting of hydrogen atoms and substituted and unsubstitutedhydrocarbon groups and heterocyclic groups, and R3 is a group selectedfrom the class consisting of substituted and unsubstituted hydrocarbongroups.

6. A method of producing a colored image in a silver halide emulsionwhich comprises developing the emulsion with .an asymmetricaldialkyl-p-phenylene diamine in the presence of a color former which is amalonic acid mono-ester mono-amide having a methylene radical attacheddirectly to the two carbonyl radicals of the malonic acid nucleus.

7. A method of producing a colored image in a silver halide emulsionwhich comprises developing the emulsion with a developing solution whichcontains an aromatic amino developing agent and a malonic acidmono-ester monoamide having a methylene radical attached directly to thetwo carbonyl radicals of the malonic acid nucleus.

8. A light sensitive silver halide photographic emulsion containing acolor former which is a malonic acid mono-ester mono-amide having amethylene radical attached directly to the two carbonyl radicals of themalonic acid nucleus.

9. A photographic element bearing at least one light sensitive silverhalide emulsion layer containing a color former of the general formula:

wherein R1 and R2 are groups selected from the class consisting ofhydrogen atoms and substituted and unsubstituted hydrocarbon groups andheterocyclic groups, and R3 is a group selected from the classconsisting of substituted and unsubstituted hydrocarbon groups.

10. A light sensitive silver halide emulsion containing as a colorformer a compound of the general formula:

wherein R is an aromatic hydrocarbon radical containing an alkoxy group,and R" is a lower alkyl group.

11. A light sensitive silver halide emulsion containingas a color formerthe mono-o-anisidide of malonic acid ethyl ester.

12. A photographic color forming developer comprising an aromatic aminodeveloping compound and the mono-o-anis-idicle of malonic acid ethylester.

13. The process which comprises developing a photographic elementbearing silver halide image in the presence of the mono-o-anisidide ofmalonic acid ethyl ester with a color coupling aromatic amino developingagent containing an unsubstituted amino group.

JOHN HUBERT REINDORR- CERTIFICATE OF commoners. Patent No. 2,269,l;81.January 1 191;.2.

JOHN HUBERT REINDORP.

It is hereby, certified that error appears in the printed specificationof the above numbered patent requiring correction as follows: Page l',second column, line 20, for "malonis" reed malonio--; page 2, secondcolumn, line 5, in the for-mule, for "NC" read --NH--; and that the saidLetters Patent should be read with this correction therein that the samemay conform to the record of the case in the Patent Office.

Signed and sealed this 5rd. day of March, A. D.- 19)+2.

Henry Van Arsdale, (Seal) Acting Commis sioner of Patents.

